Avoid the urge to do email during meetings. Laptops and BlackBerries have made it possible to do email almost anywhere and anytime. While it may seem like an efficient use of time, doing email (obviously) distracts you from what brought you into the room in the first place: the meeting! All too often, hard-working people schedule meetings to present important updates or proposals, or to review and discuss key issues, while the audience is clearly heads down in their laptops doing email. The speaker is literally alone in a crowded room.
Not only is this extremely rude, but from a business process model, if you consistently do email during meetings, you will effectively not be present in most of the meetings you attend. As a senior person in an organization (or one aspiring to be), your attention at meetings is, believe it or not, frequently required.
The optics on this kind of behavior are also pretty bad. To build an image of yourself as a person who is informed, engaged, and engaging, keep yourself focused on the meeting, not on the email.